Teeth are a very special kind of organ. Half way between a bone and some connective tissue, teeth are living little organisms, or can be thought of as self contained little ecological systems. Like the analogy implies, teeth are alive, and they can die. But because they are so hard, and so resistant, they can stick around for quite some time after they die. A dead tooth can fulfill the functions it did in its life for years to come, if it is properly maintained.